NOVEL SENSORY RESPONSES IN PSEUDOMONAS

芳香族化合物包括污染物、致癌物和消毒剂。 许多细菌，包括一些病原体，可以生长在各种各样的这些 化合物. 芳香物质可以通过细胞膜扩散， 细菌被认为没有特定的机制， 识别细胞外介质中芳香族化合物的存在。 最近， 然而，芳香族化合物已被证明是某些细菌的化学引诱物 并且已经发现假单胞菌合成诱导型化学受体， 苯甲酸酯和许多其它芳族酸。 拟议的研究将 探讨苯甲酸酯化学感受的机制和分子基础。 的 从恶臭假单胞菌中克隆苯甲酸盐化学感受器基因区 并对其分子结构进行了检测。 基因的数量和大小 将分析苯甲酸盐化学感受器操纵子指定的产物 和定点诱变将用于定义和表征 操纵子的调控区。 生理学方法将补充 分子方法，并用于检查亚细胞定位的 苯甲酸盐化学感受器，并确定如何感觉信息， 由化学感受器接收的化学物质流向细胞趋化性的其余部分， 机械. 由于苯甲酸酯是亲脂性的并且具有芳香族结构， 苯甲酸盐化学感受器很可能具有结构特征 这些化学感受器与那些被充分研究过的 其他细菌系统，也可能苯甲酸盐 化学感受器具有独特的细胞内位置。 这些研究 应该提供关于细菌感官行为的新信息， 将军 这些研究也将有望增加我们对 当细菌遇到芳香酸时， 在环境中，他们将增加相对较小的银行， 目前存在的关于遗传组织的知识， 假单胞菌

Aromatic compounds include pollutants, carcinogens, and disinfectants. Many bacteria, including some pathogens, can grow on various of these compounds. Aromatics can diffuse through cell membranes and for this reason bacteria have been thought not to have specific mechanisms to recognize the presence of aromatics in the extracellular medium. Recently, however, aromatics have been shown to be chemoattractants for some bacteria and Pseudomonas has been found to synthesize inducible chemoreceptors for benzoate and a number of other aromatic acids. The proposed research will explore the mechanism and molecular basis of benzoate chemoreception. The benzoate chemoreceptor gene region from Pseudomonas putida will be cloned and its molecular organization examined. The number and sizes of gene products specified by the benzoate chemoreceptor operon will be analyzed and site-directed mutagenesis will be used to define and characterize the regulatory region of the operon. Physiological approaches will complement molecular approaches and be used to examine the subcellular location of the benzoate chemoreceptor and determine how sensory information that is received by the chemoreceptor flows to the rest of the cellular chemotaxis machinery. Because benzoate is lipophilic and has an aromatic structure, the benzoate chemoreceptor quite probably has structural characteristics that are very different from those of the well-studied chemoreceptors of other bacterial systems and it is also possible that the benzoate chemoreceptor has a unique intracellular location. Thus these studies should provide new information about bacterial sensory behavior in general. These studies will also be expected to increase our understanding of initial interactions that occur when bacteria encounter aromatic acids in the environment and they will augment the relatively small bank of knowledge that presently exists about the genetic organization of pseudomonads.